The rapid outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) resulted within the coronavirus disease 2019 (COVID-19) pandemic. Typically, COVID-19 causes mild infection; nevertheless, some individuals experience post-acute sequelae, or long COVID, that persist for a chronic period. 

Several post-COVID conditions (PCC) have been identified, including fatigue, respiratory symptoms, body aches, and neurocognitive dysfunction. PCC adversely affects day by day activities for a minimum of one month following SARS-CoV-2 infection.

Study: Point Prevalence Estimates of Activity-Limiting Long-term Symptoms Amongst United States Adults ≥1 Month After Reported Severe Acute Respiratory Syndrome Coronavirus 2 Infection, 1 November 2021, Image Credit: Maridav / Shutterstock.com

Background

A greater understanding of the prevalence of PCC could help formulate evidence-based prevention and management strategies, in addition to the optimal allocation of resources to combat this condition.

At present, scientists face several challenges in defining PCC and determining its prevalence. That is primarily because of the presence of non-specific symptoms and the gap in knowledge regarding the duration and pathophysiology of PCC. Moreover, there’s an absence of long-term follow-up reports on PCC.

A recent Journal of Infectious Diseases study addressed the aforementioned research gap and developed a model-based approach to estimate the purpose prevalence of PCC amongst U.S. adults on November 1, 2021.

Concerning the study

The present study estimated the variety of adult U.S. residents experiencing PCC on November 1, 2021. While developing the model, scientists chosen the previously reported activity-limiting PCC symptoms related to SARS-CoV-2 infection.

PCC point prevalence estimates were developed using two primary data sources. First, the entire variety of adults who were prone to developing PCC on November 1, 2021, was estimated using infection reports from the U.S. Centers for Disease Control and Prevention (CDC). The authors also used data between February 1, 2020, and September 30, 2021, from the Nationally Notifiable Disease Surveillance System (NNDSS).

To estimate the purpose prevalence of PCC, November 1, 2021, was chosen to permit for a minimum of a one-month interval between the time of infection and PCC manifestation. As well as, the consequences of the SARS-CoV-2 Omicron variant and its sublineages were also assessed.

The household Coronavirus Infection Survey (CIS) conducted by the Office for National Statistics in the UK was the second data source. CIS provided data on non-hospitalized adults with mild or asymptomatic acute SARS-CoV-2 infection.

Study findings

Within the U.S., roughly 36.3 million SARS-CoV-2 infections were reported by September 30, 2021, which included 53% females and 47% males. About 64% of adults were between 18 and 49 years old, 66% of whom were symptomatic but didn’t require hospitalization. Furthermore, about 28% of the infected population was asymptomatic, and 6% required hospitalization for acute infection.

COVID-19 cases peaked between December 2020 and January 2021, with a record of 10 million SARS-CoV-2 infections. During this era, the Delta variant was the dominant circulating strain within the U.S.

For 22%, 44%, and 34% of infected individuals, the time between infection and November 1, 2021, was between one and 6 months, seven to 12 months, and greater than 12 months, respectively.

The model-based approach estimated that on November 1, 2021, three to 5 million U.S. adults were experiencing activity-limiting symptoms of PCC. Considering the underreporting and underdiagnosis of COVID-19, 4.3-9.7 million adults were estimated to be living with activity-limiting PCC at the moment. 

Previous studies have reported the dynamic prevalence of PCC, which relies on temporal changes related to circulating SARS-CoV-2 variants. Subsequently, a greater population-level immunity will occur with higher vaccination coverage and continual infection by the SARS-CoV-2 variants.

The present study revealed that some activity-limiting PCC symptoms persist for weeks to months after SARS-CoV-2 infection. Subsequently, there’s an urgent need for more epidemiological and clinical research to find out the chance aspects for PCC. 

Strengths and limitations

One in all the important thing strengths of this study is the utilization of national surveillance data on COVID-19, together with longitudinal household survey reports of people with mild symptoms or those that remained asymptomatic after SARS-CoV-2 infection. This can be a latest dimension, as most existing studies have focused on the event of PCC after severe or acute infection.

The estimates of the present study are subjected to certain limitations. For instance, differential PCC risk was not considered for individuals who experienced reinfection because of limitations in survey data.

Through the study period, most COVID-19-positive CIS participants were unvaccinated. In consequence, the authors did not determine activity-limiting PCC based on vaccination status across sex, age, and severity of the infection.

The newly developed model didn’t account for differences between populations in accordance with socio-demographic characteristics, underlying health conditions, and vaccine coverage and products, all of which may influence PCC development.

Despite the restrictions, the present study indicated that hundreds of thousands of U.S. adults were experiencing activity-limiting symptoms of PCC on November 1, 2021. This model could possibly be used as a foundation for future research to find out PCC prevalence.

Journal reference:

• Tenforde, W. M., Devine, O. J., Reese, H. E., et al. (2023) Point Prevalence Estimates of Activity-Limiting Long-term Symptoms Amongst United States Adults ≥1 Month After Reported Severe Acute Respiratory Syndrome Coronavirus 2 Infection, 1 November 2021, The Journal of Infectious Diseases 227(7);855-863. doi:10.1093/infdis/jiac281